1. Field of the Invention
The present invention relates to a ultrasonic-welding apparatus which can measure the face-deflection of work pieces, such as a reel joined by the ultrasonic-welding, and an optical sensor for ultrasonic-welding apparatus, a rotation sensor for ultrasonic-welding apparatus, and a location controlling method of the optical sensor for ultrasonic-welding apparatus.
2. Prior Art
Generally, a reel, onto which a magnetic tape is wound, is stored in the magnetic tape cartridge, which is used as recording medium such as a computer and videotape. The reel is formed by welding a reel hub and one flange together using the ultrasonic-welding apparatus. The reel hub is composed of a shaft, onto which a magnetic tape is wound, and other flange which are united together into an integral body.
Since the flange of the reel functions as a guide for winding a magnetic tape with sufficient accuracy, the parallelism between one flange and the flange of another side needs to be achieved with extreme precision. For example, in the case of the reel with a diameter of 100 mm, the face-deflection of a flange must be achieved within 0.18 mm. When the deflection of the dimension between both flanges is large, the problems, such as the imperfect winding, damaging on the edge of a magnetic tape, poor recording, and the tape jamming, may occurred.
Conventionally, the face-deflection of the flange of another side (located at the welded side) was measured along the following manner, specifically, after welding the flange of the another and the reel hub together by the ultrasonic-welding apparatus, the reel after welding is moved to the cradle from the welding apparatus for measurement. Then, the height of the top face of the flange of another side is measured with a dial gage on rotating the cradle. The distance between both flanges had been measured by the man power using a micrometer and the like. After recording the measured data on paper, these data were further inputted into a computer.
Since above described measurement works are carried by man power, great number of man-hours had been needed. Thus, two workers and much tact-time were required at each manufacturing line of reel. Since the measured data was inputted into a computer after once recording the measured data on paper, the operation of such works were complicated and there was also fear of the incorrect recording by posting or input mistake. Furthermore, the measuring apparatus of a face-deflection needed to be placed apart from the ultrasonic-welding apparatus, and the working space for the measuring apparatus is also required.
Therefore, automation of these measurement works has been desired. Still more preferably, it have been desired that the ultrasonic-welding apparatus which can continuously perform the operations from the welding to the face-deflection measurement of the work pieces on the condition where the work piece, such as reel, is mounted on the ultrasonic-welding apparatus.
Meanwhile, in order to measure the face-deflection of the work piece after welding with accuracy, the detection of the location of a work piece is required. For achieving this detection, an optical sensor, such as a transmission-type laser sensor, may be used.
Generally, an optical sensor is composed of a light-emitting device and a light-receiving device. When arranging the optical sensor on the cradle for the face-deflection measurement, the location of the light-emitting device and the light-receiving device is determined at both sides of the reel so that the reel is located between the light-emitting device and the light-receiving device. That is, location of the light-emitting device and the light-receiving device is determined so that the run direction of the laser light and the central axis of the light-receiving image should become parallel and perpendicular to the receiving surface of the cradle, respectively.
When the laser light is emitted from the light-emitting device to the region, where the one flange and the another flange of the reel are contained, while the cradle onto which the reel is mounted is rotating, the flange part of the light-receiving image becomes shade. The face-deflection of the reel thus will be detected by checking the change of the shade of the light-receiving image in the perimeter of the reel.
In the conventional optical sensor arranged on the cradle for the face-deflection measurement, however, the location of the light-emitting device and the light-receiving device was not adjusted after arrangement. When the optical sensor is simply arranged on the ultrasonic-welding apparatus for automating the operation from the welding to the face-deflection measurement, therefore, the displacement of the location of the light-emitting device and the light-receiving device may be caused by the vibration of the ultrasonic-welding apparatus.
As a result of the displacement of the location, the run direction of the laser light becomes less parallel to the receptacle side of the cradle. The central axis of the light-receiving image becomes less perpendicular to the receptacle side of the cradle. The physical relationship between the flange of the reel mounted on the cradle and the light-emitting device and/or the light-receiving device thus will be changed from the initial physical relationship of those.
Consequently, the displacement between the detected face-deflection, which is detected by the transmission-type laser sensor, and the actual face-deflection of the reel will be arisen, and the detection accuracy of the face-deflection of the reel thus will be dropped. Therefore, there has been required that the optical sensor which does not causes such problems even if it is applied to the ultrasonic-welding apparatus, i.e., the optical sensor for ultrasonic-welding apparatus.
Moreover, since a cover for preventing the dispersion of the noise accompanying with the ultrasonic excitation or the dust under welding is arranged on the ultrasonic-welding apparatus so that the part relate to the welding, the work piece mounted on the cradle will be covered. Thus the visual checking whether or not the reel is rotating normally during face-deflection measurement cannot be carried out.
For checking the rotation of the reel in this case, the arrangement of the rotation sensors, such as a rotary encoder, is required. When the rotation sensor is arranged into the ultrasonic-welding apparatus, arrangement of the rotation sensor near the rotors, such as the reel, may be disturbed depending on the composition of the ultrasonic-welding apparatus. Furthermore, when a rotation sensor is arranged within the adverse environment, in which dust or the like is contained, such as inside of the ultrasonic-welding apparatus, the durability of the rotation sensor may be fallen.
Therefore, there has been required that the rotation sensor for ultrasonic-welding apparatus which can detect the rotation of the work piece even if the location of the rotation sensor is distant from the work pieces, that is, the location where does not affected by the environmental condition.
The first object of the present invention is to provide the ultrasonic-welding apparatus, which can attain the above-mentioned requirement, and which can automatically achieve both measurement of the face-deflection the work piece after welding and the welding of work pieces, such as a reel for a magnetic tape.
Moreover, the second object of the present invention is providing the optical sensor for the ultrasonic-welding apparatus, which can achieve the measurement of the face-deflection a work piece without dropping the measurement accuracy, and providing the adjustment method of the optical sensor.
Furthermore, the third object of the present invention is to provide the rotation sensor for the ultrasonic-welding apparatus, which can detect the rotation of the work piece from the position distant from the work piece.
According to the present invention, which attains these objects, there is provided an ultrasonic-welding apparatus comprising; a cradle, onto which two work pieces of to be welded and for welding are mounted in piles, and which can rotate around the axis vertical to the welding surface of said work piece of to be welded; a welding hone which carries out a welding using a supersonic in the condition of having sandwiched the two work pieces between said cradle; and a transmission-type laser sensor which measures the fixed part of the work pieces of after welding by the irradiation of the laser light which runs parallel to said welding surface, and said transmission-type laser sensor measures the fixed part of the work piece after welding, which is rotating on the cradle, in the condition that said welding hone is apart from the work piece of after welding.
In the present invention, the ultrasonic-welding apparatus, in which the operations of the face-deflection measurement of the work piece after welding and the ultrasonic-welding can be carried out, is supplied. In this apparatus, since the welding horn leaves from the work piece after welding, the work piece of after welding will be in free condition. Thus, when the laser light, which runs parallel to the welding surface of the work, is irradiated to the work pieces from side direction while rotating the work piece centering on the axis vertical to the welding surface by rotating the cradle, the location and the dimension of the work piece can be measured. As described above, since the work piece is rotating, when the measurement of the fixed position is carried out along the circumference of the work piece, the measurement of the face-deflection, which is caused by the welding will be carried out. Since the work piece is rotating, the face-deflection of the work pieces which is caused by the welding will me measured by measuring the fixed position along the circumference of the work pieces.
According to the rotation sensor of the present invention, which attains above described objects, there is provided a rotation sensor for ultrasonic-welding apparatus, which detects the rotation of a rotor comprising; light-emitting means, which emits a light to a detecting object which rotates with the rotation of said rotor, and light-receiving means, which receives the light emitted from said light-emitting means.
In the present invention of the rotation sensor, the light emitted from the light-emitting mean is reflected or penetrated at the detecting part, and the light affected by the detecting part is received at the light-receiving part. Since the position of the detecting part is varied by the rotation while receiving light, time unit until the light, which is reflected by the detecting part, is received, and time unit during light-receiving/non-receiving of the light, which penetrated the detecting part, is received are changed. Thus, the rotation of the rotor is detected by the change of these time unit.
According to the adjusting method of the optical sensor for an ultrasonic-welding apparatus, which adjusts the location of said optical sensor having light-emitting means, which emits a light to a detecting object, and light-emitting means, which receives the light emitted from said light-emitting mean, wherein an adjusting member which interrupts the part of the light emitted from the light-emitting means is arranged, and forms the light-receiving image affected by said adjusting member using the light which is received at said light-receiving means, the method comprising the step of: a first adjusting process, in which the light-emitting means and the light-receiving means are moved around the axis vertical to the light emitting direction, and adjusts the location of the light-emitting means and the light-receiving means based on the light-receiving image which is changed by the movement of the light-emitting means and the light-receiving means; a second adjusting process, in which the light-emitting means and the light-receiving means are moved around the axis parallel to the light emitting direction, and adjusts the location of the light-emitting means and the light receiving means based on the light-receiving image which is changed by the movement of the light-emitting means and the light-receiving means.
In the present invention, the light-receiving image affected by the adjusting member is formed by receiving the light, which is interrupted or reflected by the adjusting member. With the first adjusting process, the change of the thickness of the adjusting member by the variation of the light-receiving image is detected, and the position around the axis vertical to the light emitting direction of the light-emitting mean and the light-receiving mean to the adjusting member is adjusted. Then, with the second adjusting process, the change of the limit position of the adjusting member is detected by the variation of the light-receiving image, and the position around the axis parallel to the light emitting direction of the light-emitting mean and the light-receiving mean to the adjusting member is adjusted.